Rangers administrators have confirmed three other bidders have expressed an interest in buying the club after Bill Miller withdrew his offer.
American tycoon Miller - who was named preferred bidder on Thursday - informed Duff and Phelps on Tuesday of his plans to withdraw from the process.
David Whitehouse, joint administrator, said: "As a consequence of Mr Miller's bid being accepted, three other bidders have come forward to express their interest in buying the club and these offers are being evaluated with the utmost urgency."
Administrators opted for Miller's £11.2million bid over a rival offer from Sale Sharks owner Brian Kennedy and the Blue Knights consortium.
The American had been hopeful of completing his takeover by the end of the season, albeit he was seeking clarification over sanctions imposed on Rangers by the football authorities.
Duff and Phelps revealed that Miller ended his interest in the club because he was "uncomfortable" with a number of issues.
Whitehouse said: "We can confirm that Mr Bill Miller has decided not to complete his purchase of Rangers Football Club.
"Since Mr Miller was announced as preferred bidder on Thursday of last week, it is regrettable that more progress could not be made to further the sale of the club.
"We have been informed by his advisors that there were a number of issues with which he felt uncomfortable including legacy contracts, the limitation of potential revenue streams and the expectation of required investment.
"As in any company takeover, the selection of a preferred bidder does not guarantee the completion of the sale.
"In this case, with time and money for Rangers running out quickly, it was essential to move the process forward with urgency.
"Mr Miller's bid was deliverable to creditors and was the only deliverable bid on the table at that time. We had no other unconditional bid.
"Given the fact that Mr Miller did not enter into an exclusivity agreement, we informed all other known potential bidders at the time the door was not closed.
"As a consequence of Mr Miller's bid being accepted, three other bidders have come forward to express their interest in buying the club and these offers are being evaluated with the utmost urgency.
"There is every opportunity for these bidders to now complete the purchase of the club prior to the end of the season."
It is understood the three bidders - two from abroad and one from the UK - made their interest known to administrators last week when Miller was named preferred bidder.
They are understood to be new bidders, rather than fresh interest from Kennedy and/or the Blue Knights.
However, it is understood owner Craig Whyte has been in touch with Kennedy with regards selling his shares, with Whyte still believing he has a key role to play in the future of the club.
Miller last month unveiled his plans for Rangers which would create what he described as an "incubator" company while Duff and Phelps aimed to take the club out of administration through a Company Voluntary Arrangement.
Explaining his decision to withdraw his interest in the Glasgow giants, Miller said in a statement released to Press Association Sport: "As soon as I was announced as preferred bidder for Rangers, my team began to press ahead with our due diligence.
"Until then, information had been limited to what was made available in the internet data room and questions addressed to the administrators and their staff.
"In addition, I had preliminary discussions with the Scottish footballing authorities and limited discussions with Ally McCoist.
"Upon being named preferred bidder, discussions with Rangers staff started and discussions with all interested parties intensified.
"We continued to work through the holiday weekend in order to meet a very compressed schedule.
"By late Monday night, it became clear to me that preliminary information, discussions and analysis were, unfortunately, more optimistic than reality.
"Having no intention of negatively affecting the potential outcome of the club's future and after hearing the message from Rangers supporters and fans loud and clear ("Yank go home!"), I notified the administrators today that I have withdrawn my bid for Rangers and will not be moving forward.
"I am deeply disappointed as I had considered the opportunity to bid for one of the most historic football clubs in the world, an honour and a privilege.
"I wish Rangers fans, supporters and employees my very best. I hope all your dreams and wishes come true. You certainly deserve it.
"I am most disappointed that I won't have the opportunity to walk into Ibrox Stadium on the day of an Old Firm match as my friends tell me the hair on my arm will stand up and I will never witness such passion and spirit at any sporting event.
"God Speed, Rangers!"
Jon Pritchett, chief executive of Club 9 Sports, tonight explained that Miller had discovered what he felt were years of mismanagement when he began his due diligence after being named preferred bidder on Thursday.
The American businessman also baulked in the face of "vitriolic" emails from fans who feared his newco plan would lead to the liquidation of the original club, and general uncertainty surrounding a number of issues.
These included the future of players, who might not have been obliged to join his new company, and as yet undecided sanctions from the Scottish Football Association and Scottish Premier League.
Club 9 Sports were initially involved in a consortium with Miller before announcing they had pulled out but Pritchett said he was still personally advising his friend, who made the bulk of his money in the tow-truck business.
Pritchett told Press Association Sport: "There were three contributing factors to his decision not to go forward.
"There are big legacy costs as a result of doing things poorly over a number of years, structural and commercial problems.
"It would be a hard time turning things around and implementing structural changes and discipline. Such changes would have made Bill very unpopular given the way things have operated.
"Even after Bill announced his austerity measures last week there were people within the club asking how much money was available to be spent. It would take a fairly large amount of money to keep it from dying."
Pritchett added: "The second factor is some of the contingency liabilities: are the players coming or going? What are the final decisions with regard to the SFA and SPL and sanctions?
"The third factor was more about the environment. It was a fairly inhospitable environment for Bill.
"He was getting hundreds of emails every day - vitriol and expletive-filled - saying 'Go home Yank'.
"Bill felt like it was a pretty unwelcoming environment. He would have had to do a lot of things that would make him less popular.
"With that combination of factors, Bill asked himself if it was really worth spending part of his children's inheritance on this. He decided this morning that it wasn't."
A Scottish Premier League vote on financial fair play proposals, which could affect Rangers, was adjourned again on Monday, this time until May 30, following a five-hour meeting at Hampden.
New rules would see greater penalties for clubs in administration, while clubs who undergo an "insolvency transfer event" could be docked 10 points for two seasons and see their SPL income slashed by 75% for three years.
What did emerge from the meeting was a proposal for all the clubs to vote on whether or not a Rangers newco should be allowed into the SPL.
Under current rules, an application for transfer of shares to a newco would be ruled upon by the SPL board.Rangers have also lodged an appeal with the Scottish Football Association after being hit with a 12-month embargo on signing players over the age of 17.
Rangers administration timeline:
February 13 - Rangers lodge their intention to go into administration at the Court of Session in Edinburgh. Owner Craig Whyte says the bill for the major tax case over the use of Employee Benefit Trusts under Sir David Murray could amount to £75million.
February 14 - Rangers appoint administrators Duff and Phelps after a court battle with Her Majesty's Revenue and Customs. They are immediately docked 10 points by the Scottish Premier League, leaving them 14 behind Celtic. Murray expresses surprise at the timing of the club's move into administration.
Duff and Phelps reveal that HMRC lodged their petition to take Rangers into administration over the non-payment of about £9million PAYE and VAT since Whyte's 2011 takeover.
February 16 - Administrators reveal "several expressions of interest from parties not connected to the club" and express concerns over Whyte's running of the club.
February 17 - Whyte expresses confidence that investigations will prove "every penny has been accounted for".
The Scottish Football Association launch an independent inquiry into the activities of Rangers, specifically whether Whyte is "fit and proper" to hold a position in the game. Rangers are denied permission to re-sign striker Daniel Cousin, whose impending arrival they had announced before going into administration.
February 21 - It is confirmed that the club's £18million bank debt was paid off with future season ticket money from Ticketus, a fact Whyte had denied three weeks earlier.
February 23 - Rangers director of football Gordon Smith and chief operating officer Ali Russell agree to leave the club. Strathclyde Police receive a report from administrators over the club's financial dealings.
February 27 - Rangers are fined £50,000 by the PLUS Stock Exchange for failing to disclose owner Whyte was previously disqualified as a director.
March 2 - The SFA confirm they will investigate claims made by former Rangers director Hugh Adam that payments made to players were not disclosed to the governing body. Duff and Phelps postpone a final decision on cuts after refusing an offer from players to defer wages.
March 3 - Administrators say redundancies are "likely" as Rangers lose 2-1 at home to Hearts.
March 5 - The SPL confirm that their board have instigated an investigation into the alleged non-disclosure of payments made to players by Rangers. Rangers administrators consider a proposal from players overnight after failing to reach consensus over wage cuts.
March 7 - Rangers director Dave King claims liquidation is inevitable. Duff & Phelps announce they are accelerating the sale of the club after failing to agree cost-cutting measures with the playing staff, while joint administrator Paul Clark says there is "no realistic prospect" of the club being able to meet criteria needed to play in European competition next season by the March 31 deadline.
March 8 - The SFA declare Whyte is unfit to hold a position in football and confirm that the club is facing a charge of bringing the game into disrepute.
March 9 - Rangers administrators announce a package of wage cuts with players that have "directly prevented substantial job losses among non-playing staff both at Ibrox and Murray Park".
March 15 - The SFA issue Rangers with notices of complaint over alleged breaches of five disciplinary rules and Whyte over two alleged breaches.
April 4 - Duff and Phelps confirm they received four bids for the club.
April 11 - Duff and Phelps confirm they have been forced to delay the announcement of a preferred bidder due to proposed changes to SPL rules.
April 19 - Brian Kennedy is told his revised verbal bid for Rangers is not "capable of acceptance".
April 23 - Rangers receive a 12-month embargo on signing players and owner Craig Whyte is banned for life.
April 25 - Strathclyde Police give security advice to the three members of the SFA judicial panel who handed out punishments to Rangers after "abusive and threatening communication".
May 3 - American businessman Bill Miller granted preferred bidder status by Duff and Phelps.
May 8 - Miller withdraws bid for Rangers. Duff and Phelps later confirm three other bidders have expressed an interest in buying the club.